When I run the second example on play.golang.org, the output I get is: This program will get 10 IDs from the id channel, print them and terminate 0a90

When I run the second example on play.golang.org, the output I get is: This program will get 10 IDs from the id channel, print them and terminate 0a90333b6c0f5519b6e5f7ea2d541fb1793b957d 58 bytes written af2f87580bb3562b58f2ad076e25f76ebf8fec75 0 bytes written 4491029b704d192be5a31eb0c35dfe516274d173 58 bytes written d97a9080d01e9a8a11d0152d3df34f1c90f5cf16 0 bytes written 130c9fda35c98c7e8922d6ea24bb873838cfdcbd 58 bytes written 0e385bcc65efb6bac8ced67639c32b374d31ae57 0 bytes written 550413e7244dd40cf3df52634bb341dc166708b2 58 bytes written 49cfddab6ff9123ad237f03176927329349e186b 0 bytes written 12abf2ab19e52065b3f7367a57f6f8ecd4968b44 58 bytes written 0755254307f5f9b90829381fa797b5f26081cd5f 0 bytes written Why does the count alternate between 58 and 0?